John Haeber photographs the inside of an abandoned sugar refinery by using a technique called light painting. Betteravia, CA. 6.1.07 (Photo by Matt Mallams/ Freelance for the San Francisco Chronicle)

Photo: Matt Mallams

John Haeber photographs the inside of an abandoned sugar refinery...

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Inside the light-sealed, 75-foot tall storage silo at Betteravia. A spiral staircase within the support column leads to the top, providing roof access. Being inside was a very surreal experience, as sounds would echo and reverberate, creating an extremely eerie environment.
Scott Haefner/Special to the Chronicle
Special to the Chronicle / Scott Haefner

"Keep quiet and keep down, this building is active," says BryGuy, his pointed finger catching a flashlight behind him. "And no more flashlights." Everything snaps to black. Between the clanks and buried explosions of the acres-long factory to our right, the only other sound is the percussion of footfalls along the dirt road on which we're running. "There's a guard up there, be careful," BryGuy announces, heading deeper into knee-high grass. A hundred yards in front of us our target appears: two steel silos jutting stories-high on a flat, black field. BryGuy kneels at the crossroads, and in the shadow of a flickering streetlight whispers: "OK, that's it. That's where we're going."

Tonight's event has so far been executed with militaristic precision, each member moving with the economy and alertness of a soldier on a dangerous reconnaissance mission. But this group isn't wearing fatigues and night-vision goggles; they're in baggy shorts, untied shoes and black hoodies. The triggers they're flipping aren't on guns, but on beat-up flea market flashlights. And this isn't a war zone. It's a weedy field in front of an abandoned sugar refinery along a rural road an hour south of San Luis Obispo. It's Friday night at 11:30, and Central California's Urban Explorer Meet has just begun.

What is an urban explorer?

Urban exploration is the examination of off-limits or seldom seen parts of man-made structures. Unlike other adventurers, such as rock climbers or spelunkers, urban explorers shun the natural world in pursuit of more closely examining and understanding the inner workings of our constructed world, of seeing civic society in its real, raw, unpainted, unplastered and unprettied state. It's internal city touring, but without guides, double-decker buses, maps or directions. It's about going where people aren't supposed to go.

Indeed, a few kids trespassing in old buildings is nothing new. What makes urban exploration different is that it is not a few kids - it is tens of thousands of people of varying ages and professions. And it's not just old buildings: It is subbasements, engine rooms, mine shafts, train tunnels, drains, cemeteries, hospitals, decommissioned ships, nuclear missile silos and more. Urban exploration is a worldwide phenomenon with its own fanzines, conventions, culture, ethics, periodicals, books, movies, MTV specials and clubs from Russia to Australia, Canada to Chile. And it's growing.

The vetting: Urban Explorer bootcamp

All this newfound attention has made many longtime urban explorers cautious. They've adopted online pseudonyms such as Darkwolf, Shadowsix, SkullmanX and AllieKat to hide their identities. Discoveries are no longer openly shared online, but handled like carefully guarded secrets among a small network of trusted cronies. Newcomers are viewed skeptically, and in some cases made to withstand lengthy mental and physical vetting before they are allowed to join other members on explorations.

Which was exactly why I was shoving myself under a chain-link fence and into a broken window on the ground floor of a radiation-polluted former Navy building on a warm Wednesday night in June. Repeated attempts to solicit a response from urban explorers online had gone nowhere for months. Rumors were that law enforcement had been monitoring some Web sites after discovering that burglars were scanning them for tips on how to break into buildings. A last-ditch effort at RSVPing to the Central California Urban Explorer Meet in San Luis Obispo (to which I was not invited) spurred enough curiosity for the host, BryGuy, to write me back - to tell me directly that I couldn't come. I pleaded, explaining that I was neither a cop nor a fed, that I would not compromise the safety of others. BryGuy eventually relented, and said I could possibly come, depending on how I handled myself during a short test run with an established Bay Area explorer named Tunnelbug.

A week later, Tunnelbug pulls into a dirt lot opposite an abandoned fire station in an industrial park south of San Francisco. In khakis and a new Banana Republic jacket, he looks nothing like the goth-rock, nose-pierced misanthrope I had envisioned him to be. His real name is Jonathan Haeber, a 25-year-old copywriter from Richmond. He is soft-spoken and polite, with a meditative demeanor. "We can walk from here," he says in a hushed voice, grabbing a tripod from his backseat.

Tunnelbug leads me through small holes in fences, past swinging gates, down alleys and through 50-foot-high empty warehouses. "See those buildings over there," he says, pointing a half mile in the distance. "I've heard that's one of the most toxic sites in the U.S." We pass one of many dirt mounds covered in black tarps, the plastic sides flapping in the wind. "That plastic is supposed to stop the radiation, PCBs and chemicals in the ground from seeping into the air," he says with a laugh. "I don't think it's working too well."

Tunnelbug stops in the delivery port of a Wal-Mart-size six-story building and pulls a fence from a broken window. He wends his rubbery limbs through an impossibly small hole, turns and says: "You think you can fit?" Standing about a foot taller than him, I attempt to follow, ripping my pants leg on a rusted barb but making it in. "You're a natural," he says, helping me down. He clicks on his flashlight and walks quickly into a matte-black hallway. I follow a few steps behind, picking glass from my fingers.

Through a catacomb of blown-out rooms covered in spooky graffiti and rodent droppings, we emerge into the building's grand foyer, a sweeping acres-wide room surrounded by three-story-high glass curtain walls. Pigeons fly through the gauzy light of the dirty windows, their helicopter flutter reverberating through the room. Dramatic shadows from the 30-foot-tall columns cover black puddles of water. The room looks grand and cinematic, a moody backdrop to a big-budget, post-apocalyptic thriller. It's dazzling. At the center is an escalator extending three floors high at a 45-degree angle. "When this building was constructed," Tunnelbug explains, "this was once the tallest escalator in the world."

The building was built by the Navy between 1944 and 1947, and was used to research and produce navigational equipment for battleships and submarines. It was also a major headquarters for the study and practice of military cryptography, as evidenced by the codebooks and crypto machines haphazardly left behind in piles throughout the third and fourth floors. Closed in 1974, the building has been abandoned ever since.

"Anything spray-painted orange means it was checked with a Geiger counter for radiation - whether it passed or not, I'm not sure," Tunnelbug says as he follows me through two piles of typewriters - all painted orange. "As far as I can tell it's really low level. I mean, people worked here for 20 years and were fine," he says, pausing. "Just don't eat the paint chips."

In an electric control room opposite the fourth floor, fist-size buttons line a wall, each boasting baffling and somehow frightening names like "Gyro Supply Switch," "Current Ammeter" and "Phase 2, 3." I pull at the buttons' hand-painted plaque and ask Tunnelbug if I can take one. "No, actually, we shouldn't take anything," he says. I ask why. He replies matter-of-factly: "If it's gone, then other people who come here won't be able to enjoy it."

This preservationist ethos separates urban explorers from other trespassers or vandals. As Ninjalicious, a.k.a. Jeff Chapman, states in the urban explorer manual "Access All Areas," urban exploring should be in accordance with the Sierra Club axiom: "Take nothing but pictures, leave nothing but footprints." But Chapman argues that urban explorers shouldn't leave footprints, either. They shouldn't leave any trace. And they especially shouldn't steal. Not only is this advice practical - getting caught stealing could elevate a trespassing conviction from a misdemeanor to a felony - it's also altruistic. For many urban explorers, like Chapman and Tunnelbug, these sites are not trash heaps but historic landmarks. They should be treated as such.

We exit the sixth-story staircase and enter a football-field-size observation roof deck constructed entirely of windows. Centered through a 10-foot broken frame behind us is a crystal-clear postcard panorama of the city, the Bay Bridge and Alameda. Tunnelbug points to a huge dock and crane to the south, explaining that this is where the Naval Radiological Defense Laboratory brought several ships that had returned from nuclear weapons tests at the Bikini Atoll in the Marshall Islands. Allegedly, a number of these ships were buried here. "You can see the incentive to build here; it's such an amazing view," Tunnelbug says, setting up his tripod. "If it just weren't so completely radioactive."

An hour later we exit the building. As I go to retrieve my car in China Basin, Tunnelbug shakes my hand and says, "OK, I'll see you on Friday in San Luis." I'm in.

The history of "hacking"

Though the name urban exploration was coined in a 1996 edition of the fanzine Infiltration, people have been adventuring behind the walls, roofs and stairs for long as cities have existed.

In 1793, Philibert Aspairt, considered the first "Cataphile," explored Paris' storied underground catacombs by candlelight - his body was found 11 years later. One of the 19th century's most famous and celebrated poets, Walt Whitman, was also an avid urban explorer, publishing his forays into Brooklyn's abandoned Atlantic Avenue Tunnel in 1861. In the 1920s, Parisian Dadaists brought metaphysics into the hobby, organizing tours through a deserted church and other sites "which really have no reason for existing." Back in the United States, MIT students led excursions into steam tunnels and rooftops around campus in the late 1950s; they called their practice "hacking" - a term that decades later was adopted into techie parlance.

With the growth of the Internet in the early 1990s, urban exploration's popularity exploded, generating hundreds of Web sites, and, for the first time, allowing members from around the world to exchange photographs, information and tips on how to get into sites. One of these sites, www.uer.ca, has more than 18,000 active members.

That's where BryGuy, a 19-year-old Cal Poly student, posted an invitation for members to attend a Central California group exploration. The plan was to meet in the parking lot of a fast-food restaurant south of San Luis Obispo on the first full moon of June. With black sweatshirts and headlamps, standing in a loose semicircle near a dirty pickup, the group of 10 wasn't hard to spot amid the crowds of cowboys and high schools students that had gathered on Friday night. Most of the explorers were students from Cal Poly, but a few, including Tunnelbug and Scott Haefner, a 32-year-old Web designer at the U.S. Geological Survey, had traveled hundreds of miles from the Bay Area.

We load in our cars and head west, stopping up a dirt road across from two enormous silos. Tonight's mission is at a sugar refinery built in 1899 that is spread out over 200 acres in the barren farmland south of Pismo Beach. At its busiest in 1982, the refinery processed a staggering 11 million pounds of beets into sugar per day. In 1988, a dust explosion and fire burned eight workers, seven critically. The factory never fully recovered. Sugar beet acreage and cheaper overseas imports forced its permanent closure in 1993. The factory grounds were partially demolished in 1997, but a mechanical room and two seven-story refining silos remain.

We duck beneath a fence and enter a tunnel submerged in a few inches of stagnant water. The air is thick and acrid. Daniel Ketchum, a 19-year-old civil engineering student at Cal Poly, opens a small steel door with a wheel on its center, turns and says: "There's a step down here; just follow me."

We lean in and are instantly engulfed in pure blackness. Hermetically sealed and constructed entirely of steel, the silos inhibit even the slightest amount of air, light or sound from coming in or out. Because sound has nowhere to go, it bounces around the curved walls, creating a disorienting delay-effect. A scratch on the coat becomes a roar; a click of a flashlight splashes like a downpour of rain; a cough explodes. We stood there in absolute darkness, repeatedly turning to reply to a person who sounded as if he was whispering behind us - but was really 100 feet across the room. It is dizzying, having your senses so thoroughly rearranged, but liberating too, creating a feeling of almost weightlessness. Days later Scott Haefner, the Bay Area explorer, admitted: "That was one of the most surreal, amazing experiences I think I've ever had."

It was 2 a.m. by the time I returned to my seedy motel room, removed my molasses and cobweb-covered clothes and collapsed on the bed. On the television, the local public access channel was airing a program called "Faces of Meth," which looped grotesque before-and-after photos of methamphetamine-abusing local people along with perky pop gems cribbed from a local radio station. I don't think the programmers were aware of the hazardous irony of playing "You Make Me Feel Like a Natural Woman" behind close-ups of bleeding, toothless, drug-ravaged mouths. I wondered which part of urban exploring was more difficult: controlling your vertigo while climbing an exposed 70-foot spiral staircase or spending downtime in economically depressed hick towns.

Detour to the cannery

For adamant explorers like Tunnelbug, downtime was not an issue - it was just another opportunity to explore. On a Tuesday night two weeks after the Central California meeting, he asked if I wanted to join him on a trip to an abandoned tuna cannery along a smelly creek a 10-minute drive from my house.

"There are pretty much an endless number of places to discover," he says, sitting on a 40-year-old plastic foam block on the third-floor refrigerator room. "I think unraveling things, looking at things, and trying to deduce why the place closed down - that's what I like about these places."

Tunnelbug explains that the factory in which we're sitting was closed four decades ago after two women in Detroit died of botulism from tuna that was packed there, causing a nationwide panic that devastated the industry. Sales fell 35 percent, spurring extensive layoffs and factory shutdowns. In an attempt to regain public confidence, the government confiscated all tuna packed at the plant and buried it beneath 10 tons of garbage in a dump next to Candlestick Park. The source of the botulism was never found. The factory was closed in 1963, and has been dormant ever since.

As abandoned buildings such as the cannery lose one purpose, they gain another. Nature returns in dazzling and poignant ways: Rust paints steel doors in multicolored patinas; ivy envelops offices and break rooms like a clenched fist; feral cats rest in vents. It's this gray zone between civilization and the natural world that Tunnelbug finds especially attractive. "As a photographer, I think the decay, how these buildings age, is really beautiful."

He leads me to a small room near a fenced-in exit. "Be careful, there's a lot of drug paraphernalia on the floor," he mentions. "Last time I was here, in that corner, next to a bunch of needles, there were these negatives of a wedding, a bunch of pictures of this guy and his wife together," he says with a nervous laugh.

Tunnelbug explains similarly unfortunate discoveries, like finding a soiled diaper hundreds of feet down at the bottom of a Titan nuclear missile site in Colorado. "The air was so polluted with benzene and diesel gas - you couldn't even breathe in there without a respirator - and someone was living there!" And then there was the time he happened upon 2,000 antique chest X-rays in a mining town in the Rocky Mountains. "Every single X-ray showed discoloration, silicosis or some kind of lung disease." But perhaps the most disturbing story in urban exploration is Chapman's foray through a slime-infested tunnel beneath a cemetery. There, he walked through brownish-yellow mucus stalactites, which, allegedly, were generated from decomposing bodies buried in the ground above.

What's the attraction to risking fines, jail time and one's health to wade through the sadder, sicker parts of human nature alone on weeknights through the city's trash heaps? Why not go on a hike through Tilden, a stroll along Fort Funston? "In this world, everything has been pretty much discovered," Tunnelbug says. "It's nice to see things people have never seen."

Final mission: Going underground

Two weeks before meeting Tunnelbug at the tuna factory, the second day of the Central California meet started on the side of a two-lane highway north of San Luis Obispo. We head east for an hour over parched hills and snaking lines of mountain bikers to a dirt parking lot. There are others in the lot, and they watch us curiously as we pull flashlights, headlamps, water bottles and gloves from our trunks and head up a small trail.

"There's a rope down here; follow me," BryGuy says once up the hill. We rappel down a cliff into the mouth of a cave, from which a frigid and musty breeze exhales into the hot afternoon air. At the cave entrance the group stops to put on sweaters and jackets and heads into a black tunnel. We follow miniature railroad tracks past 100-year-old bottles and rusted carts that shuttled 228,000 pounds of mercury from the mine from 1872 to 1961. At its height of production, the mine had 7,000 feet of tunnels that wove through several hundred feet of earth. Some of these tunnels are still accessible, though getting to them is arduous - and dangerous.

When an area, like this mine, is closed and left to sit for decades, it is not only nature that returns - but also the laws of nature. Dry rot, fire damage, razor-sharp rusted nails and unstable earth are constant menaces at most abandoned sites. It is the explorer's responsibility to avoid death or injury in these areas, to be solely responsible for one's self. In a modern society so buffered and baby-proofed with guardrails, signs, tour guides, maps, safety lids, safety bars and safety belts, relearning these basic self-reliant survival skills for urban exploration is scary, and doesn't come easy. Screwing up is costly, sometimes deadly. But the payoff for most urban explorers is worth it: a freedom to do absolutely anything you want, whenever you want, to whatever you want, if just for a little while.

Tunnelbug holds onto a rusting ladder with one hand and his camera in the other, jerkily stepping his way down a pitch black hole that leads deeper into the mine. The epicenter of the mine is illuminated by a single shaft of natural light that streams in through a collapsed hole in the crust of the hill above us. From the base level on which we stand, tunnels and caves shoot out like fingers in every direction. The group disperses.

I follow David Ketchem and two others, Laura Anselmo, a 19-year-old nursing student, and her 20-year-old friend Sky Morales down an embankment into a door-size opening of a tunnel. The deeper we go, the smaller the hand-chiseled walls become until eventually, 300 feet inside, the tunnel ends. Our headlamps throw light on the walls and ceiling, which glisten with translucent beads. "That's probably the mercury ore," explains Ketchum.

"Lets turn off the lights for a minute and see if we can see anything," he asks. We stand in the blackness, in a thick and dead silence, a quarter-mile of rock surrounding us in all directions. I'm not sure for how long; time stops. With a clearing of his throat, Ketchum turns on his light and in a low, raspy voice asks: "How many places in the world today can you go that are this dark and this quiet?" He turns and begins his ascent back outside. "That's why I do this."